A steam turbine is usually used in a power plant for driving a generator or in an industrial plant for driving a machine. As a result, steam serving as a flow medium is fed to the steam turbine and is released in the steam turbine in an output-producing manner. After its release, the steam usually arrives at one of the condensers mounted downstream of the steam turbine and condenses there. The condensate is then fed as feed water to a steam generator and then again arrives in the steam turbine after its evaporation, so that there is a closed water-steam circuit. A plant with the relevant components, i.e. particularly with a steam turbine and a steam generator is also designated as a steam turbine plant or steam power plant.
A combustion chamber in which a fuel is burnt is usually assigned to the steam generator of such a steam power plant. The hot flue gases usually arising during the combustion of fossil fuels are then conveyed through the steam generator, in which case they are used for steam generation by means of heat exchange with the flow medium conveyed in the water-steam circuit.
For the combustion of fuel, fresh air or combustion air needs to be fed to the combustion chamber assigned to the steam generator. As a result, the combustion chamber is usually connected on the inlet side not only to a fuel pipe but also to a fresh air pipe for the combustion air. Via the fresh air pipe, the combustion air is fed to the combustion chamber, in which case the comparatively high pressure level required for feeding the combustion air into the combustion chamber is provided via a pneumatic conveyor mounted in the fresh air pipe.
When designing such a steam power plant, a customary design goal is a particularly high plant efficiency ratio when converting the energy stored in the fuel to electrical energy or energy that can be used in other operating conditions. Therefore, for example, the plant process of such a steam power plant, particularly its operating parameters, is specified or selected in such a way that for thermodynamic reasons a particularly favorable transfer of energy can be obtained. To this end, among other things, the combustion air to be fed to the combustion chamber is usually pre-warmed to a comparatively high temperature level because this favors the efficiency ratio of the actual combustion process. Such a pre-warming of the combustion air can be carried out, for example, inside the actual steam generator, in which case the energy content is partially used for pre-warming the air during the combustion of the generated flue gas.